Rapid spatial expansion and population increase of invasive lionfish (Pterois spp.) observed on natural habitats in the northern Gulf of Mexico

The invasion of lionfish (Pterois spp.) into the Gulf of Mexico has been well documented but to date few studies have presented analysis on abundance trends to evaluate population status and trends. We used trawl and reef fish video survey data to analyze abundance trends from 2010 to 2019. The trawl and camera survey data evaluated show a rapid increase of lionfish through 2016-2017 with subsequent stabilization or decreases in 2018 and 2019. Lionfish occupied multiple natural habitats across the northern Gulf of Mexico, have a strong affinity for hard bottom habitats with sponge, but no preference relative to low versus high relief reef types. Population growth trends indicated faster population growth in trawl surveys as compared to video indices. Incidental catch of sponge in trawls, which primarily occurred in the eastern Gulf of Mexico, was a significant variable explaining lionfish catch. Interestingly, there were few lionfish captured in the western Gulf of Mexico suggesting that the low-relief soft-bottom in that region is less suitable for lionfish. Artificial habitats in the western Gulf of Mexico could be providing necessary hard-bottom habitat for lionfish, however, survey data analyzed in this study cannot provide inference as these surveys are not conducted on those habitats. Careful consideration must be taken when implementing lionfish removal programs given a potential for increased population growth when harvest does not achieve overfishing. In addition monitoring of community level effects will be needed as predation and indirect competition for resources could potentially negatively impact native species.